The book "For Magnus Chase: Hotel Valhalla Guide to the Norse Worlds" will excite readers who are waiting for "The Hammer of Thor". It is a 176-page book in a small size, with colorful illustrations throughout. Helgi, the hotel manager, created this book for every hotel guest so they don't have to answer so many questions at the reception. It contains brief entries about the deities, mythical heroes, and fantastical creatures from the nine Norse worlds and includes additional material like interviews, newspaper articles, short stories, and more. The tone is humorous, complementing Rick's series.